The objective of this research is to develop recommendations for the application of dynamic lane use control based upon their human factors implications. For this research, dynamic lane use control should be interpreted broadly so as to include applications such as reversible lanes, hard shoulder running, dynamic junction control, and toll plazas.
Tasks 1 through 6 are complete and work has begun on the human factors research. The following interim deliverable is available for download: Task 2 Technical Memorandum: Summary of Effective Practices.
Note: It is expected that the principal investigator will make presentations to the relevant Technical Committees of the National Committee on Uniform Traffic Control Devices (NCUTCD), following approval of the Task 2 summary and the draft final deliverables.
Task 1. Analyze, describe, and critique pertinent research on driver behavior associated with dynamic lane use control. Include completed research and research currently underway, both domestic and international.
Task 2. Catalog dynamic lane use control and other operational strategies that present similar traffic control challenges. Identify traffic control approaches used by state, local, and international transportation agencies for these strategies and collect their evaluations of the operational and safety effectiveness of these approaches. Within 6 months of contract execution, develop a summary of effective practices, including hybrid traffic control approaches based upon those implemented by various agencies.
Task 3. Identify critical human factor variables (e.g., level of congestion, approach speeds, rationale for lane use change, complexity of the driving environment, driver familiarity, regional differences) that may influence driver behavior associated with dynamic lane use control. Define and justify behaviors (e.g., failure to obey lane closed messages, driver uncertainty, driver compliance) that can be used as metrics to evaluate the effectiveness of the alternative traffic control approaches during the human factors research in Task 7. This should be done for drivers approaching, entering, within, and exiting the dynamic lane use control zone and for the transition period when the lane use control is changing.
Task 4. Identify alternative and complementary ways (other than traffic control devices) to present the information to drivers and discuss how these could be taken advantage of in the future. Examples include navigational systems, digital maps, and connected vehicle technologies.
Task 5. Develop a detailed work plan for the human factors research in Task 7, including the scenarios that will be used. The scenarios should include the specific dynamic lane use control application, the approach to be tested, the ranges of independent human factor variables, and the performance assessment metrics. As the budget permits, field data should be used to calibrate and validate any simulation-based analysis.
Task 6. Prepare an interim report on the information developed in Tasks 1 through 5.
Task 7. Carry out the human factors research as presented in the interim report and modified based on the discussion at the interim meeting.
Task 8. Prepare content that agencies can use to develop outreach material for educating the public on the intended response to the traffic control approaches for dynamic lane use control.
Task 9. Submit a final report documenting the entire research effort and including proposed content for the Manual on Uniform Traffic Control Devices (MUTCD) and the outreach material content as appendices. In addition, prepare a stand-alone technical memorandum titled “Implementation of Research Findings and Products.”
Active Traffic Management (ATM) strategies provide the “ability to dynamically manage recurrent and non-recurrent congestion based on prevailing and predicted traffic conditions” (FHWA’s Active Traffic Management website). New traffic control devices and approaches are needed to support these strategies and many of those devices and approaches are not included in the MUTCD. Furthermore, the effectiveness of the devices and approaches in obtaining the desired response from drivers are not well understood. Inefficiencies in traffic control lead to reductions in safety and operational efficiency, precisely what ATM is intended to improve.
One of the commonly used ATM strategies is dynamic lane use control. The FHWA defines dynamic lane use control as dynamically closing or opening individual traffic lanes as warranted and providing advance warning of the closure(s) (typically through dynamic lane control signs), in order to safely merge traffic into adjoining lanes. Drivers are required to identify and understand the intended lane usage and make an appropriate maneuver safely and smoothly.
In many existing dynamic lane use control installations, acceptable travel lanes are identified by text-based or graphical overhead signage such as a green arrow or a dynamic speed limit sign. Closed travel lanes are most often identified by an overhead red ‘X’. In some locations, ground-mounted signing is also used to communicate lane use to drivers. For example, Seattle, WA uses shoulder- or barrier-mounted signs that read either SHOULDER OPEN TO TRAFFIC or SHOULDER CLOSED. Other locations use signs to indicate the type of traffic allowed in the controlled lane (frequently buses). Various forms of static pavement marking or colored pavements are used to support the signs. There is little consistency and limited guidance in the methods used for communicating dynamic lane use control to drivers and little research on the most effective approaches. There are a number of other operational strategies that present similar traffic control challenges and the traffic control approaches should be consistent.